SEOUL , South Korea -LRB- CNN -RRB- -- North Korean leader Kim Jong-il tapped his son to join the powerful National Defense Commission -- a move analysts say makes the latter the heir apparent , South Korean state media said .

Kim Jong-il has appointed his youngest son and his brother-in-law to the National Defense Commission .

`` Kim Jong-un had been appointed to a low-level post , called ` instructor ' at the National Defense Commission days before the first session of the 12th Supreme People 's Assembly meeting was held , '' South Korea 's Yonhap news agency reported , quoting a source .

CNN was not able to independently confirm the report .

The secretive North Korea shields its internal affairs from international scrutiny . And often , the only news coming the Communist nation is reported by its neighbor South Korea .

The two countries have technically remained in a state of war since the Korean War ended in 1953 , although relations have warmed somewhat in the last few years . The Korean conflict ended in a truce , but no formal peace treaty was ever signed .

The 25-year-old picked for the North Korean defense commission is the youngest of Kim 's three sons , Yonhap said .

The move comes two weeks after Kim added his brother-in-law Jang Song Thaek to the military board . Analysts said Jang will serve as a caretaker for the successor , Yonhap said .

Jang , who has been married to Kim 's sister since 1972 , is considered his right-hand man , according to Yonhap .

Kim was reappointed this month as chairman of the military board in his first major public appearance since a reported stroke in August .

His recent health problems and long absence from public functions prompted speculation on whether he was ready to groom an heir to the world 's only communist dynasty .

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North Korean leader Kim Jong-Il 's son joins National Defense Commission

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South Korean media says move makes Kim Jong-un his father 's heir apparent

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25-year-old is youngest of Kim 's three sons